Impact hammer



Oct. 15, 1963 c. w. PEwTHERs I 3,107,083

' IMPACT HAMMER Filed July 1, 1960 2 She'etS-Sheei 1 Arran/v5 VJ C. W.PEWTHERS oct, 15, 1963 IMPACT HAMMER 2 Sheets-Sheet 2 Filed July l, 1960United states Patent llll IMPACT HAP/EMER Charles W. Pewthers, Bryan,Tex. Filed .iuiy i, weil, Ser. No. 40,454 2 Siaims. (El. 253-2) ri'hepresent invention relates to improvements in impact hammers of the poweractuated type.

There have been many power hammers proposed in the past. Most impactpower hammers `of the heavy `duty type available tothe trade are of thepneumatic type. While these provide impact suicient so that they havebeen received in the trade, they are disadvantageous in that they arerelatively large and complicated in design, have a high noise level, arelimited in that they must be driven at a constant speed in order todevelop maximum power, they are relatively inellicient in that the airpressure is vented to the atmosphere in use, and the auxiliary equipmentis quite expensive, for example the air compressors required to supply asufficient volume of air pressure for the operation of the hammer.

Other type power impact or percussion tools have been proposed, such aselectric motor driven impact drills and the like; however, these havegenerally been restricted to applications requiring not much force, forexample, these are not suitable for impacting yand breaking up hardformations, such as pavements, hard fonnations and the like, but laregenerally used in impact type electric drills and other light dutyapplications.

it would be highly `advantageous to provide an impact type hammer forheavy duty use in which considerable power is produced, which is highlyelicient, which p-rovides a large force in a very small package, whichis of simple design, in which the noise level of the tool is low and bywhich the rate of impacts for a particular impact hammer may be variedwith a minimum loss of power. In addition, it would be highly desirableto provide a hydraulic impact hammer, that is one that is actuated byhydraulic force, and which is suliiciently powerful to be used for heavyduty use, for example, for breaking up hard formations, paving, cuttingasphalt, chipping, slagging, riveting, rock drilling and the like. Itwould also be advantageous to provide such an improved impact hammerwhich may be used as `a hand held tool or applied to power-actuatedtools such as excavation devices, buckets, shovels and the like. Itwould also be advantageous to provide an impact hammer in which theimpact shaft rotates, for example, for transmitting rotation to adrilling tool for drilling in hard materials, such as rock, concrete andthe like. The present invention is directed to such an improved powerimpact hammer.

lt is therefore an object of the present invention to provide animproved power impact hammer which overcomes the previously-mentioneddisadvantages of other power impact hammers.

Yet a Vfurther obiect of the present invention is the provision of arugged power impact hammer which develops a tremendously large force ina very small package, which is of simple design, and in which the noiselevel is reduced.

Yet a further object of the present invention is the provision of animpact hammer powered by a hydraulic motor `and hydraulic system.

Yet a further object of the present invention is the provision of animproved impact hammer powered by a hydraulic motor and a hydraulicsystem, which hydraulic system includes a jacketing arrangement forcooling the impact hammer which is particularly useful when beingoper-ated as a hand tool.

Yet a further object of the present invention is the provision of animproved power impact hammer which 3de-m83 raice is less expensive tomanufacture than other impact hammers, requires considerably lessexpensive auxiliary equipment for its operation, and in which theoperating costs are materially reduced.

Still a further object of the present invention is the provision of apower impact hammer in which variations in the speed or rate of impactcan be made while developing maximum or close to maximum power percycle.

Yet a further object is the provision of a hydraulic impact hammer whichis of increased eiciency yover others and in which very little power orenergy is lost during its operation.

Yet a further object of the present invention is the provision of animproved power impact hammer which is yof suiciently small size so thatit may readily be incorporated in various earth excavating devices, suchlas power excavating machinery used in moving earth such as front endloader buckets, shovel buckets, clam shell buckets, back hoe buckets orany type of power shoveling device and the like.

Yet a further object of the present invention is the provision of animproved impact hammer which is of small enough size and of minimumvibration and noise to be readily used as a hand held tool for heavyduty use.

Other and further objects, features and advantages will be apparent fromthe following description of presently preferred embodiments of theinvention, taken in conjunction With the drawings, in which likecharacter references designate like parts throughout the several views,and where FIGURE l is an elevational view, partly in section,illustrating .a hydraulic impact hammer according to the invention,

FIGURE 2 is a schematic view illustrating a satisfactory hydraulicVsystem for use with the impact hammer of FIGURE 1,

FIGURE 3 is an -exploded view of components of the impact hammer ofFIGURE 1, and

FIGURE 4 is -a fragmentary view, partly in section, illustrating amodication.

Referring now to the drawings, Iand particularly to FGURE l, the impacthammer is generally designated by the reference numeral 10 and includesthe hydraulic motor l2, the housing 14 to which are secured the handles16 and i3 `for operating the impact hammer as a hand tool. As will beapparent later, one of the handles 16 is lalso a valve control forcontrolling the rate of flow of hydraulic fluid to the hydraulic motorl2 for controlling the rate of rotation of the motor l2 and hence thera-te of impact.

The motor housing 14 is shown .las an integral part of the upper bodymember 2li and various structural elements, such as the arms 22 and 24-yare provided to releasably secure and releasably mount the hydraulicmotor i2, the :handles i6 and i8 to the body member 20. Since anydesired arrangement may be utilized for this purpose, :and theparticular form of connecting the parts together, as such, do notconstitute the present invention, no further description thereof isdeemed necessary or appropriate.

Extending from and driven by the hydraulic motor l2 is the `output shaft26 which is connected by a flexible coupling 2S to the combined rotorand coupling 36 so that rotation of the output shaft 26 rotates thecombined rotor `and coupling Si?.

The combined coupling yand rotor includes the splines 32 which t intothe llexible coupling 28 and, while not shown, suitable splines, keysand the like are provided on the motor output shaft 26 so that rotationis transmit-ted from the output shaft 26* through the flexible coupling2S to the combined rotor and coupling 30. As illus- 3 trated, the outputshaft 26 -is connected in axial alignment with the coupling 30.

An antifriction assembly generally designated by the reference numeral34 is provided adjacent the inner end of the combined rotor and coupling30 which, of course, reduces friction and particularly any thrust actionimparted to the combined rotor and coupling 3i?.

A counterbore 49 is provided in the outer end of the combined rotor andcoupling 3i) which is provided with a plurality of axially-extendinggrooves 42 for reception of the upper end 44 of the impact shaft 46which is provided with a complementary set of axially-extending grooves48 into which the antifriction balls 50 are provided.

The coupling arrangement between the combined rotor and bushing 36 andthe impact shaft 46 provides an axially-aligned connection and is highlyadvantageous in that it provides a very simple, rugged andeflicientlyreliable connection which permits limited axial movement ofthe impact shaft 46 with a minimum of friction and yet provides anonrotatable connection so that the motor 12 driving the motor outputshaft 26 through the exible coupling 2S and thus the combined rotor andcoupling 3i? transmits this rotation to the impact shaft 46.

The impact shaft 46 is provided with an annular enlargement 52yintermediate its ends and includes the inwardly facing annular shoulder54 which serves as a stop for one end of the compression spring 56, theother end of which stops against the outwardly facing annular shoulder Sof the combined bushing and coupling Sil.

As best shown in FIGURE 3, to which reference is now made the outerportion of the enlarged intermediate section 52 of the impact shaft 46is provided with a single cam face 60 which includes the annularinclined cam face or helix 62 provided with the single, abrupt,axially-aligned shoulder surface 64 which permits the axial travel ofthe shaft in an outward or downward direction in response to the actionof the coil spring 56.

Referring again to FIGURE 1, the impact shaft 46 and a portion of thecombined rotor and coupling'S are disposed within a generallycylindrically-shaped housing member 31 which, preferably, is releasablysecured to the housing member 20, such as by threading as illustrated,so that the various parts may readily and easily be assembled orreplaced and repaired.

Disposed within the outer end of the body member 31 is the nose cone 33which, preferably, is releasably secured `to the body member 31, such asby threading as illustrated,

again for the purpose of ease of assembly and making repairs andreplacement of parts.

The nose cone 33 is provided with a cooperating annular cam face orhelix 66 which is complementary to the cam 52 and, accordingly, includesthe inclined helical cam face 68 provided with the single, abrupt,axially-aligned shoulder 7 0.

It should be noted that the helical cam surfaces 62 and 66 of the cam6i) and the nose cone 33, respectively, are continuously in engagementthroughout their length either at or shortly after the impact anddecrease in engagement during rotation until they are completelyreleased at the drop olf point of the axially-aligned shoulders 64 and70. This is highly advantageous in that maximum strength is provided sothat a rugged and efficiently reliable impact hammer is provided forrugged and heavy duty, such as pavement breaking, asphalt chipping,slagging tools, riveting guns, rock drilling, hard formation breakingand any type of percussion work which requires powerful impacts.

The nose cone 33 is provided with the seals 7 0' adjacent the threadedportion 72 and the seal 74 adjacent the outer end of the central bore 76of the nose cone 33 through which the outer end 78 of the impact shaft46 extends. While a flat end is shown any desired percussion type toolmay be secured thereto or, if desired, the percussion tool might beformed as an integral part of the shaft 78, as desired.

A modification is illustrated in FIGURE 4, to which reference is nowmade, and to which the reference letters a have been added to partscorresponding to those of FIGURES l-3 for convenience of reference. l

Essentially, the modification of FIGURE 4 includes the nose cone 33a, towhich is threadedly or otherwise secured a generally tubular retainerbody Si? which slidably receives the multi-sided percussion type tool Siincluding a multi-sided portion or shank S2 fitting into the coactingextensions 83 extending from the end of the impact shaft 78. Thisarrangement transmits the rotation from the impact shaft 46a to thepercussion tool Si although a nonrotatable connection may be provided,if desired. As illustrated, the percussion tool Si terminates in a sharpor spike point 86.

The percussion tool S1 is removably secured in the retainer body bymeans of the spring type latch S8, one end 9) of which is disposed toengage the annular stop member 92 on the tool Si, the spring 94releasably retaining the latch 8S in the position illustrated. Thus, areadily releasable latching arrangement is provided for securing to andremoving from the impact hammer any desired tool.

Since any desired arrangement may be utilized for securing a particulartool to the impact hammer 10, such as that illustrated at 33 in FIGURE4, or the end of the impact shaft 78, as shown in FIGURES l and 3 mayactually form the impact tool, no further description thereof is deemednecessary or appropriate.

As previously mentioned, one of the important aspects of the inventionis the operation of the impact hammer hydraulically. A suitablehydraulic arrangement is schematically illustrated in FIGURE 2, to whichreference is now made. As there illustrated, a suitable hydraulic pumpIdil is provided which is connected by the hydraulic line 102 extendingfrom the reservoir 164. The ilow line 166 is provided from the pump 106to the motor l2, the ow of hydraulic liquid from the pump I6@ and in theflow line 166 being regulated by the regulator valve I6 forming part ofthe handle, if desired, as previously mentioned in connection withFIGURE l, although it may otherwise be located.

Referring again to FIGURE 2, the hydraulic system advantageously alsoprovides a cooling system for the impact hammer 10 which is particularlyadvantageous when used as a hand tool, and includes the flow line llt?extending from the flow line 106 to the motor 12 to the jacket 111disposed about the cam enlargement 69 with a return line 103 to thereservoir 104 to complete the hydraulic circuit. It will be understood,of course, that any conventional and suitable hydraulic pump 16),hydraulic motor 104, regulator Valve I6 and the like may be utilized toprovide the required torque or rotational force to the impact shaft 46.Also, by regulating the valve 16 the rate of impact is controlled byregulating the speed of the motor 12. In addition, when utilizing thecooling feature of the hydraulic system, which may be omitted ifdesired, but which is highly advantageous when using the impact hammeras a hand tool, the hydraulic liquid maintains the impact hammer liticool. Also, the hydraulic motor considerably reduces the noise level,for example with respect to pneumatic type impact hammers, and thehydraulic pump 160, hydraulic reservoir 104 and flow lines are con--siderably less expensive than, for example, air compressors and thelike. In addition, the hydraulic drive system. is highly advantageousfor use in connection with various tractors and mobile earth movingequipment inasmuch as these all contain their own hydraulic system andcontrols.

In this event, of course, the regulator valve 16 would bef at a positionadjacent the operator, the handles 16 and 18 omitted so that control ofthe impact hammer is convenient to the operator along with the othercontrols for various power excavating machinery, for example, front endloader buckets, shovel buckets, clam shell buckets, back hoe buckets orany type of shoveling or earth moving device. In addition, the verysmall and compact size and.

the considerable power and force generated advantageously permits theimpact hammer to be installed and used with such power excavatingdevices with a minimum of interference with their normal operations.

In operation, hydraulic liquid is provided to the hydraulic motor 12,the rate of flow being regulated by the regulator valve 16 which therebyregulates the speed 0f the motor 12 and thus the rotation of the impactshaft 46. During rotation of the impact shaft 46 the cam surfaces 62.and 66 engage to compress the spring 56, then suddenly release theimpact shaft 46 to the energy built up in the spring S6 when theaxially-aligned shoulders 64 and 70 are just past opposite one another,the impacting cam thereby releasing the impact shaft 46 to provide animpacting blow. In the event the full blow of the impact shaft 78 is notabsorbed by that which is being impacted, the cam surfaces or faces 62and 66 are in substantial engagement substantially along their length toprovide a very rugged hammer and anvil surface.

It is further noted that by the combined rotor and bushing 30 and theantifriction connection described between the inner end 44 of the impactshaft 46 and the rotor and coupling 30, along with the action of thecoil spring 56, is such to provide minimized shock or impact to themotor end of the tool 10. Also, when utilizing the hydraulic coolingarrangement described, a major portion of the heat built up in the toolis carried away by the hydraulic field as part of the hydraulic circuit.

Additionally, a completely sealed body is provided in which the movingparts may be lubricated completely for minimum friction.

The impact hammer of the present invention is therefore well suited andadapted to attain the objects and ends and has the advantages andfeatures mentioned as well as others inherent therein.

While presently preferred embodiments of the invention have been givenfor the purpose of disclosure, along With representative and typicaluses thereof, other uses thereof will occur to those in the various artsin which the invention may be used and changes in details andarrangement of parts may be made which are within the spirit of theinvention as dened by the scope of the appended claims.

What is claimed is:

1. A hydraulic impact hammer comprising,

a housing,

a rotary hydraulic motor mounted on the housing, the output shaft ofwhich extends axially into the housing,

an impact shaft mounted axially in the housing for both rotation andlimited axial movement relative thereto,

a driving connection connecting the output shaft to the impact shaft,

a cam formed on the impact shaft,

a cam cylinder fixed to the housing,

said impact shaft rotatably extending through the cam cylinder,

a pair of complementary mating faces on the cam and cam cylinder, eachsaid face comprising substantially circumferentially extending helicalsurfaces terminating in an abrupt, axially aligned shoulder surfacepermitting sudden axial travel of the shaft in one direction,

a compression spring within the housing and around the shaft foractuating the shaft axially in said one direction,

a cooling jacket carried by the housing adjacent the cam faces, and

hydraulic flow lines providing an inlet to and an outlet from thecooling jacket.

2. In an impact hammer including a housing, an impact shaft mounted inone end of the housing for both rotation and limited axial movementrelative thereto, cam means in the housing permitting sudden axialtravel of the shaft in one direction, and a spring within the housingactuating the shaft axially in said one direction, the improvementcomprising,

a rotary hydraulic motor carried by the housing adjacent the other end,the output shaft of which extends into the housing,

a driving connection between the output shaft and impact shafttransmitting rotation to the impact shaft from the output shaft andpermitting limited movement therebetween,

a cooling jacket carried by and exteriorly of the housing adjacent thecam means, and

hydraulic flow lines connecting the cooling jacket with the hydraulicoutlet of the motor and to the source of hydraulic liquid forcirculating hydraulic liquid in said cooling jacket.

References Cited in the rile of this patent UNITED STATES PATENTS770,455 Douglas Sept. 20, 1904 2,191,608 Coates Feb. 27, 1940 2,457,565Kott Dec. 28, 1948 2,736,543 Slomer Feb. 28, 1956 2,752,889 Leavell July3, 1956 2,780,106 Lovequist Feb. 5, 1957 2,806,672 Selberg et al Sept.17, 1957 2,905,168 Henry Sept. 22, 1959 FOREIGN PATENTS 715,182 GermanyDec. 15, 1941 1,066,765 France June 9, 1954

1. A HYDRAULIC IMPACT HAMMER COMPRISING, A HOUSING, A ROTARY HYDRAULICMOTOR MOUNTED ON THE HOUSING, THE OUTPUT SHAFT OF WHICH EXTENDS AXIALLYINTO THE HOUSING, AN IMPACT SHAFT MOUNTED AXIALLY IN THE HOUSING FORBOTH ROTATION AND LIMITED AXIAL MOVEMENT RELATIVE THERETO, A DRIVINGCONNECTION CONNECTING THE OUTPUT SHAFT TO THE IMPACT SHAFT, A CAM FORMEDON THE IMPACT SHAFT, A CAM CYLINDER FIXED TO THE HOUSING, SAID IMPACTSHAFT ROTATABLY EXTENDING THROUGH THE CAM CYLINDER, A PAIR OFCOMPLEMENTARY MATING FACES ON THE CAM AND CAM CYLINDER, EACH SAID FACECOMPRISING SUBSTAN-